NEW YORK (Reuters Health) - In patients with hepatitis C virus (HCV) and the human immunodeficiency virus (HIV), pegylated interferon and ribavirin therapy for the hepatitis produce significant metabolic improvements as well.

The effect lasts only while treatment continues, however, leaving just a modest persistent improvement in insulin resistance, researchers reported online May 4th in Clinical Infectious Diseases.

Dr. Adeel A. Butt of the University of Pittsburgh School of Medicine and colleagues studied 98 HIV/HCV patients who were participating in a study of the effect of peginterferon and ribavirin maintenance therapy on fibrosis progression. Evaluation of metabolic parameters was a pre-specified secondary aim.

Fasting levels of low-density lipoprotein, high-density lipoprotein, and total cholesterol all fell significantly while on treatment, by a median of 13, 15 and 6 mg/dL, respectively, after 16 weeks of treatment and 20, 16 and 5 mg/dL at treatment week 64.

Values were almost back to baseline at 24 weeks after treatment ended.

Triglycerides increased significantly during the first 16 weeks of treatment, by 30 mg/dL, but by week 64 the increase was no longer significant and by 24 weeks after treatment ended those levels too had return nearly to baseline.

As for insulin resistance, values of the homeostasis model assessment showed a gradual modest decline during treatment that did still persist at 24 weeks after completion.

"Whether this improvement eventually translates into a decrease in incidence of overt diabetes mellitus, or improvement of glycemic controls in those who are already diabetic, requires further investigation," the authors say.

In email to Reuters Health, Dr. Butt noted, "The effect of HCV treatment upon metabolic parameters is not well understood. Our study demonstrated a modest improvement in insulin resistance with anti-HCV treatment. This suggests an added benefit of treatment, and further justifies the need to identify and treat HCV infected patients."

He concluded, "Larger studies are needed to confirm whether treatment decreases the rate of incident diabetes in HCV infected persons."